The present invention relates to a horn switch, and in particular, it relates to a horn switch device provided in an airbag system and constructed such that, when depressed, a module cover is retracted to turn on a horn switch. The invention also relates to an airbag system and a steering wheel that include the horn switch device.
Driver-seat airbag systems mounted to car steering wheels are known in which when the module covers of the airbag systems are depressed, horn switches are turned on to sound horns. For example, Japanese Unexamined Patent Application Publication No. 10-100832 and Japanese Unexamined Patent Application Publication No. 2001-114057 describe airbag systems in which, when depressed, a module cover is retracted against the repulsive force of a spring to turn on a horn switch.
In the conventional horn switch devices, the spring has a single stage, so that the reaction force of the module cover is proportional to the pushing stroke of the module cover.
Accordingly, it is an object of the present invention to provide a horn switch device in which multistage (i.e., two-stage) springs arranged in series bias a retractable body such as a module cover to offer the advantage of improving operability.
It is also an object of the present invention to provide an airbag system and a steering wheel that include the horn switch device.
Further objects and advantages of the invention will be apparent from the following description of the invention and the associated drawings.